1. Field of the Invention
The present invention relates to a process for producing a cationic polymer emulsion. More particularly, it relates to a process for producing a cationic emulsion of polymer which has both mechanical and chemical stability.
2. Description of the Prior Art
In the manufacture of synthetic rubbers, synthetic resins and paints, aqueous emulsion polymerization using an emulsifier has been employed to produce the polymer. The conventional emulsifiers used, however, have deleterious effects on the properties of the latex or polymer produced. Further, the conventional emulsifiers can cause difficulties. Recently, pollution caused by the conventional emulsifiers has become a problem. Conventional emulsifiers are found in the waste water from the washing and filtering steps of the process for producing a polymer by emulsion polymerization, and the discharged waste water is a source of water pollution. In addition, the emulsifier that remains in the polymer causes the polymer to adhere on mixing rolls and molds.
In preparing adhesive compositions, it is necessary to use emulsion-type adhesive compositions instead of solvent-type adhesive compositions because of the air pollution caused by the solvents in solvent-based adhesive compositions. Unfortunately, the conventional emulsifiers have the effect of lowering the adhesive property of the emulsion. It has been theorized that these difficulties are caused by the bonding of the conventional emulsifiers through physical adsorption on the polymer particles in the emulsion. It is known that conventional emulsifiers can be removed from the polymer particles when heat or pressure is applied to them.
It has been proposed to produce polymer emulsions by using an unsaturated acid or a reactive emulsifier without using the conventional emulsifiers (Japanese Unexamined Patent Publication Nos. 34588/1974 and 40388/1974). However, there is no disclosure in the prior art for producing a cationic polymer emulsion.
Accordingly, there exists a need for a process which can prepare cationic polymer emulsions without using conventional emulsifiers.